Medical balloons are used in the body in a variety of applications including as dilatation devices for compressing plaque and for expanding prosthetic devices such as stents at a desired location in a bodily vessel. Because it is typically necessary for the balloon to traverse a tortuous anatomy as it is being delivered to the desired location in the bodily vessel, it is desirable for the balloon to assume as low a profile as possible.
One way to achieve a low profile is by folding the balloon to form a number of wings. Some examples of methods of forming wings on a balloon are described in U.S. Pat. Nos. 5,147,302 and 5,350,361. A common method employed to form wings on a balloon is to partially inflate a balloon and then impart an inward radial force about the periphery of the balloon using a plurality of members or “blades” which are distributed about the periphery of the balloon. As the blades move radially inward, wings are formed in the balloon.
When forming wings in balloons in this manner, however, special care must be taken to ensure that the blades do not have any sharp edges or burrs which would damage the balloon. To this end, some prior balloon folding apparatuses have blades that are equipped with a relatively soft tip of silicone or other material. However, providing the blade with a relatively soft tip may be insufficient to reduce the potential from damage to the balloon during wing formation. In addition to the above, as the tip of each blade pushes radially against the balloon, inconsistent frictional interface between each tip and the balloon material upon which they push may lead to the formation of wings having non-uniform lengths. Balloons having wings of non-uniform lengths may lead to a catheter having a larger profile when the wings are folded.
In prior folding techniques caution must be exercised to prevent the blades from applying damaging forces to the balloon and/or any structures underlying the balloon such as marker bands, bonds or hubs. Although the amount of force applied to the balloon may be reduced to avoid damaging the balloon and/or any underlying structures, sufficient force must, nevertheless, be applied to completely form the balloon wings so as to achieve the desired cross-section. Complete formation of the wing includes imparting one or more creases into each wing. The creases help the balloon to attain a reduced profile by providing wings that are relatively flat and thus are easily folded to provide the balloon with a reduced diameter. Prior methods that form the wings by closing the blades about the balloon may be insufficient to provide creases which are adequate.
In light of the above, it is a goal of the present invention to provide a wing forming method and apparatus that reduces the friction between the balloon and blades, provides for improved ability to produce wings having uniform lengths and/or provides for improved crease formation.
All US patents and applications and all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety.
Without limiting the scope of the invention a brief summary of some of the claimed embodiments of the invention is set forth below. Additional details of the summarized embodiments of the invention and/or additional embodiments of the invention may be found in the Detailed Description of the Invention below.
A brief abstract of the technical disclosure in the specification is provided as well only for the purposes of complying with 37 C.F.R. 1.72. The abstract is not intended to be used for interpreting the scope of the claims.